This SCR timer was found in an old English documentation. The SCR can be the TUIC106 and modern equivalent transistors like the BC557 for TR1 and BC547 for the others.
This 9 V battery eliminator was found in Radio Electronics magazine from June 1966. The transistor is of...
Using the ZN1034E which reaches 19 days interval, this is a simpler circuit which can be...
This analog meter circuit was found in the September 1989 issue of Radio Electronics magazine. The source...